Carburetor



M. MALLORY priu so, 1935.

CARBURETOR 2 Sheets-Sheet 1 Filed April 28, 1954 n QW; www

Tm/f

Gum/wu,

M. MALLORY April 30, 1935.,

GARBURETOR 2 Sheets-Sheet 2 Filed April 28, 1954 ll A s@ Patented pr.30,I 1935 1.999.334 cAaBUaEToa Marion Mallor Mallory Research Company,

y, Detroit, Mich., assignor to The Toledo, Ohio, a.

corporation of Delaware Application April 28, 1934, Serial No. 722,977

. 10 Claims. This invention relates to a carburetor, provided with achoke valve, and is in the nature of an improvement over the disclosurein my earlier application, Serial No. 702,051, filed December 12, 51933. The opening of the choke valve is controlled in part by suctionfrom the intake manifold and in part by the velocity of the air passingthrough the carburetor.

present form, comprises two oppositel y opening valves with fuel nozzlestherein, so that the fuel is always discharged toward the cent theintake passage. air flow and consequently the highest er line of Thegreatest restriction of velocity is directly across the fuel nozzles.The fuel is therefore atomized as it is drawn through the venturi orthrottle. After leaving the nozzles, the atomized fuel does notsubsequently strike any wall,

as is the case with other carburetors, but passes directly into thecenter oi' tively high vacuum, which atomization.

The preferred form or" a region of tends to p comparaerfect the theinvention will now be described more in detail in connection with theaccompanying drawings, in which Figure i is a vertical section takencentrally of the intake passageway, with the choke valve closed.

Figure 2 is a central vertical section taken at right angles to the thechoke valve open.

plane oi Figure l, showing Figure 3 is a plan view of the carburetorvFigure i is a section taken on the line lv-3 of Figure 2.

Figure 5 is a detail view Figure 6 is a plan view of and connections.

of the throttle control. the throttle valves The invention is hereinshown as applied to a down draft carburetor having a chamb er i@ with anair inlet it, within which is an annular seat i i for the choke valvelil. to be opened by suction The valve i is adapted from the intattemanifold, to which the lower end of the intatte passageway iti isadapted to be connected.

For this purpose, the chamber t@ is formed with a web i5 from which ahollow stem it extends upwardii! and constitutes a bearing on which thevalve i3 is reciprocably mounted. The valve G3i internally with asuction chamber ill a is formed nd alight spring it within the chamberil urges the valve toward its seat i2. A tube I9 connects the chamber ilwith the intake pasageway M. A cam or eccentric 20 is secured to aspindle 2i extending horizontally across the air intake Il and the 5spindle 2| is adapted to be rocked by any known means, either manual orautomatic, to hold the choke valve i3 positively open or partly openwhenever the motor is warm enough to take a leaner mixture.

At one side of the intake passageway it, there is a bowl 22, withinwhich the liquid gasolene is maintained at a substantially constantlevel by the usual float 23 and needle valve it controlling the inlet tothe bowl. l5

The throttle comprises two valves 25 mounted on parallel horizontalspindles 26, which are con nected to each other at one end byintermeshing gear segments 2l, so that they rock in opposite directionsin their opening and closing movements. The valves 25 are balanced sothat the vacuum on one side does not tend to hold them open. The wallsof the intake passageway conn form to the paths described by the outeredges of the valves 25, as shown at 2t, so that all of the fuel which isdrawn into the manifold passes beEL tween the valves along the centerline oi the passageway. f

As the air is drawn through the chamber it and the passageway it,gasolene is drawn' into the air stream from the bowl 22. For thispurpose, each spindle '26 has a depending tubular fuel inlet nozzle ordipper 2t extending below the liquid level in the bowl 22. The fuelpasses from the nozzles or dippers 29 longitudinally ofthe respectivespindles 26, which are also tubular, and through bores 30 in the valves25, whence it is discharged into the air stream which passes downwardlythrough the chamber ill when the throttle is open. 40

One of the valves 25 has a jet orice 3i near its tip and another orifice32 at its center. The orifice i2 acts as an air bleed to the jet orice3i when the throttle is opened to a small extent, thus causing more fuelto be discharged, but as the throttle is opened wider, the increased airow is more directly across the orice i2 and the latter ceases to be anair bleed. If the throttle is opened still wider, fuel is dischargedfrom the orifice 32, as well as from the orice The orif- 50 ces 3i and32 are so restricted that the mixture will be suciently lean during therst stages or throttle opening. The other valve 25 has a larger openingi3 at its center which comes into operation only when the throttle isfully open or nearly so, because it is pointed upward and there will beno vacuum created in it until it is turned into the air streamsubstantially at a right angle thereto. The orifice 43, therefore, playsthe role of a power jet.

An idling well 33 is formed in the wall of the passageway I4 and has anoutlet 34 and bleed 35.

In the present construction, the throttle valve itself constitutes aventuri. In other words, with the choke valve I3 open, the openingbetween the valves 25 is the most restricted part of the intakepassageway and consequently the air iiow at this point attains itshighest velocity. This not only draws gasolene from the bowl butcompletely atomizes it. The atomized fuel mixture then passes downwardlyalong the central line of the passageway directly into a region of highvacuum without striking any cold or hard surface, which would tend tocondense it again.

In fuel feeding devices, as heretofore used, the volume of the fuelcharge is usually controlled by a throttle valve having a single vanewhich defiects the fuel mixture against the side of the passageway. Thusthe fuel, if it has become atomized in the mixing chamber, tends tocondense in drops, to be again atomizedat it enters the region of highvacuum in the intake manifold. In the present construction, howev'er,the initial atomization, which is more complete than in the usualcarburetor, is retained in full and is further promotedby the projectionof the stream directly into the center of the high vacuum in the intakemanifold.

It will be noted that in the present construction, as the throttle isopened, the jet orifices are swung downwardly, so that there is anincreased iiow of gasolene from the bowl 22 in proper proportion to theincreased flow of air. Thus the fuel mixture is regulated by thethrottle without the use of metering valves.

When the choke valve I3 is used, if the engine is operating at low speedand is suddenly accelerated, the pressure within the lower end of thepassageway I4 will rise, permitting the choke valve to move towardclosed position. This maintains a degree of vacuum in the manifold,which will not only suck out more gasolene from the bowl but will at thesame time promote its atomization.

I have found, however, that if the spring I8 alone is used incontrolling the valve I3 and is made strong enough to choke the enginesulficiently for starting, it will be too stiff when the engine isrunning normally; that is, when the engine is accelerated and the vacuumdecreases, ythe valve will close up too much and over-choke the engine.I have therefore provided a weaker auxiliary spring 44 mounted in a cup45 at the top of the valve I3. This spring 44 opposes the spring I8,when the cam 20 is moved to partially or wholly open the choke, thuspreventing the Valve I3 from over-choking the engine on aceeleration.When the cam 20 is moved to choke the engine, however, the spring 44 isreleased.

In connection with this carburetor, I prefer to use the throttle controldevice shown in Figure 5. In this device, the throttle lever 36 issecured to one of the spindles 26 and is connected to a piston 31 whichoperates in a dash pot 38. In closing the throttle, the manuallyoperated rod 39 engages the lever 36 and a check valve 40 in the end ofthe dash pot allows the piston to move freely therein, but in moving therod 39 to open the throttle, it merely releases the lever 36. Thethrottle is then slowly opened by the air passing therethrough. 'I'hisopening will be facilitated if the valves 25 are unbalanced, with thegreater area at the inner side of the axis. During this gradual openingmovement of the throttle, the piston 31 gradually travels toward theopen end of the dash pot, while air bleeds into the dash pot through thebleed hole 42. Thus it is impossible to stall the engine by opening thethrottle too suddenly.

From the foregoing description, it will be seen that I have provided afuel supply device in which the throttle itself constitutes a venturiand the gasolene is fed from the bowl through the throttle directly intothe venturi, so that the highest air velocity is directly across thefuel jet nozzles, thereby insuring the best possible atomization. Thereis no' throttle between the venturi and the intake manifold for theatomized fuel to strike against and to become again condensed, as is thecase with the usual carburetors. All of the air, as well as the fuel, isdirected by the throttle toward the center line of the passageway andimmediately into the region of highest vacuum.

While I have illustrated and described the specific form of theinvention which at present seems most desirable, it is apparent thatmany of the details thereof may be considerably modified withoutdeparting from the scope of the appended claims.

I claim:

1. In a carburetor, a fuel passageway, a throttle therein constituting aventuri, and means for discharging fuel in intersecting jets along thecenter line of said venturi, the angle between the jets being adjustablein synchronism with the adjustment of the throttle opening.

2. In a carburetor, a fuel bowl, an intake passageway, a throttle valveplvotally mounted in said passageway, a fuel jet nozzle in the throttlevalve and connected with the bowl and discharging into said passagewayat a point higher than the normal level of liquid ln the bowl, thenozzle outlet being on the side of the valve axis which moves downwardlyas the valve opens.

3. In a carburetor, a.passageway having a variable venturi, a fuel inletnozzle opening into the narrowest part of the venturi and means forlowering the fuel inlet nozzle as the capacity of the venturi isincreased.

4. The combination with a fuel mixture passageway, of interconnectedthrottle valves therefor adapted to open said passageway, a leverconnected to the axis of one of said valves, a rod movable in onedirection to engage the lever and close the valves and movable in theopposite direction to release the lever, the opening movement of thevalves being completed by the velocity of the mixture stream passingtherethrough.

5. The combination with a fuel mixture passageway, of interconnectedthrottle valves therefor adapted to open said passageway, a leverconnected to the axis of one of said valves, a rod movable in onedirection to engage the lever and close the valves and movable in theopposite direction to release the lever, the opening movement of thevalves being completed by the velocity of the mixture stream passingbetween them, and a dash pot, with a bleed, connected to said lever.

6. 'Ihe combination with a fuel mixture passageway, of throttle valvestherein adapted to open at the center of the passageway, one of saidvalves having a fuel duct with small orlilces at 1,999,384 v the inneredge and at the axis of the valve respectively, the other valve' havinga fuel duct with a single larger orice located at the axis of the valve.

7. The combination with a fuel mixture passageway having an air inletformed with an annular valve seat, of a reciprocable choke valve c0-operating with said seat and adapted to be opened by suction throughsaid passageway, a spring opposing the opening of said valve, a secondspring, and means for setting said second spring to oppose the rstmentioned spring when a full choke is not desired.

8. The combination with a fuel mixture passageway having an air inletformed with an annular valve seat, of a reciprocable choke valvecooperating with said seat and adapted to be opened by suction throughsaid passageway, a spring opposing the opening of said valve, a secondspring normally idle when full choke is desired, and manually operablemeans to set said second spring to exert different degrees of oppositionto the rst mentioned spring as circumstances require.

9. 'I'he combination with a fuel mixture passageway having an air inletformed with an annular valve seat, of a reciprocable choke valvecooperating with said seat and adapted to be opened by suction throughsaid passageway, a spring opposing the opening of said valve, a secondspring normally idle when full choke is desired, and a manually operablecam directly engageable with said valve to positively open it whenchoking is not desired.

l0. In a carburetor, an intake passageway having an air inlet, twothrottle valve members within the passageway with a variable openingbetween themand fuel jets discharging in converging lines toward thecenter of the air stream directly between said valves.

MARION MALLORY.

